This research project seeks to define the nature of changes in brain structures due to recurrent episodes of depression. It is hypothesized that recurrent depression may accelerate normal hippocampal aging, perhaps through neuronal glucocorticoid toxicity resulting from depression-induced hypercortisolemia. A cross-sectional study of 40 medically healthy patients, ages 20-80, with recurrent early onset major depression and 40 pair-wise matched controls will test for differences in regional brain structure volumes, cognitive function, HPA axis function, and clinical variables.